Title: Search for a heavy right-handed W boson and a heavy neutrino in events with two same-flavor leptons and two jets at s=13$$ \sqrt{s}=13 $$ TeV

A search for a heavy right-handed W boson (W$$_\mathrm{R}$$) decaying to a heavy right-handed neutrino and a charged lepton in events with two same-flavor leptons (e or $$\mu$$) and two jets, is presented. The analysis is based on proton-proton collision data, collected by the CMS Collaboration at the LHC in 2016 and corresponding to an integrated luminosity of 35.9 fb$$^{-1}$$. No significant excess above the standard model expectation is seen in the invariant mass distribution of the dilepton plus dijet system. Assuming that couplings are identical to those of the standard model, and that only one heavy neutrino flavor N$$_\mathrm{R}$$ contributes significantly to the W$$_\mathrm{R}$$ decay width, the region in the two-dimensional ($$m_\mathrm{W_R}, m_\mathrm{N_R}$$) mass plane excluded at 95% confidence level extends to approximately $$m_\mathrm{W_R}=$$ 4.4 TeV and covers a large range of right-handed neutrino masses below the W$$_\mathrm{R}$$ boson mass. This analysis provides the most stringent limits on the W$$_\mathrm{R}$$ mass to date.

This letter reports on a search for hypothetical heavy neutrinos, N, and right-handed gauge bosons, W R, in events with high transverse momentum objects which include two reconstructed leptons and at least one hadronic jet. The results were obtained from data corresponding to an integrated luminosity of 2.1 fb -1 collected in proton–proton collisions at √ s = 7 TeV with the ATLAS detector at the CERN Large Hadron Collider. No excess above the Standard Model background expectation is observed. Excluded mass regions for Majorana and Dirac neutrinos are presented using two approaches for interactions that violate lepton and lepton-flavormore » numbers. One approach uses an effective operator framework, the other approach is guided by the Left– Right Symmetric Model. Finally, the results described in this letter represent the most stringent limits to date on the masses of heavy neutrinos and W R bosons obtained in direct searches.« less

A search is performed for third-generation scalar leptoquarks and heavy right-handed neutrinos in events containing one electron or muon, one hadronically decaying τ lepton, and at least two jets, using amore » $$ \sqrt{s}=13 $$ TeV pp collision data sample corresponding to an integrated luminosity of 12.9 fb$$^{-1}$$ collected with the CMS detector at the LHC in 2016. The number of observed events is found to be in agreement with the standard model prediction. A limit is set at 95% confidence level on the product of the leptoquark pair production cross section and β$$^{2}$$, where β is the branching fraction of leptoquark decay to a τ lepton and a bottom quark. Assuming β = 1, third-generation leptoquarks with masses below 850 GeV are excluded at 95% confidence level. An additional search based on the same event topology involves heavy right-handed neutrinos, N$$_{R}$$, and right-handed W bosons, W$$_{R}$$, arising in a left-right symmetric extension of the standard model. In this search, W$$_{R}$$ bosons are assumed to decay to a tau lepton and N$$_{R}$$ followed by the decay of the N$$_{R}$$ to a tau lepton and an off-shell W$$_{R}$$ boson. Assuming the mass of the right-handed neutrino to be half of the mass of the right-handed W boson, W$$_{R}$$ boson masses below 2.9 TeV are excluded at 95% confidence level. Lastly, these results improve on the limits from previous searches for third-generation leptoquarks and heavy right-handed neutrinos with τ leptons in the final state.« less

Search results are presented for physics beyond the standard model in final states with two opposite-charge, same-flavor leptons, jets, and missing transverse momentum. The data sample corresponds to an integrated luminosity of 35.9 fb –1 of proton-proton collisions at √s = 13 TeV collected with the CMS detector at the LHC in 2016. The analysis uses the invariant mass of the lepton pair, searching for a kinematic edge or a resonant-like excess compatible with the Z boson mass. The search for a kinematic edge targets production of particles sensitive to the strong force, while the resonance search targets both stronglymore » and electroweakly produced new physics. The observed yields are consistent with the expectations from the standard model, and the results are interpreted in the context of simplified models of supersymmetry. In a gauge mediated supersymmetry breaking (GMSB) model of gluino pair production with decay chains including Z bosons, gluino masses up to 1500–1770 GeV are excluded at the 95% confidence level depending on the lightest neutralino mass. In a model of electroweak chargino-neutralino production, chargino masses as high as 610 GeV are excluded when the lightest neutralino is massless. In GMSB models of electroweak neutralino-neutralino production, neutralino masses up to 500-650 GeV are excluded depending on the decay mode assumed. Lastly, in a model with bottom squark pair production and decay chains resulting in a kinematic edge in the dilepton invariant mass distribution, bottom squark masses up to 980–1200 GeV are excluded depending on the mass of the next-to-lightest neutralino.« less

A search is presented for physics beyond the standard model in final states with two opposite-sign, same-flavor leptons, jets, and missing transverse momentum. The data sample corresponds to an integrated luminosity of 2.3 fb –1 of proton-proton collisions at √s = 13 TeV collected with the CMS detector at the LHC in 2015. The analysis uses the invariant mass of the lepton pair, searching for a kinematic edge or a resonant-like excess compatible with the Z boson mass. Both search modes use several event categories in order to increase the sensitivity to new physics. These categories are based on themore » rapidity of the leptons, the multiplicity of jets and b jets, the scalar sum of jet transverse momenta, and missing transverse momentum. Furthermore, the observations in all signal regions are consistent with the expectations from the standard model, and the results are interpreted in the context of simplified models of supersymmetry.« less

Here, a search is conducted for new resonances decaying into a W or Z boson and a 125 GeV Higgs boson in themore » $$v\bar{v}$$$b\bar{b}$$, ℓ ±ν$$b\bar{b}$$, and ℓ +ℓ -$$b\bar{b}$$ final states, where ℓ ± = e ± or μ ±, in pp collisions at $$\sqrt{s}$$ =13 TeV. The data used correspond to a total integrated luminosity of 36.1 fb -1 collected with the ATLAS detector at the Large Hadron Collider during the 2015 and 2016 data-taking periods. The search is conducted by examining the reconstructed invariant or transverse mass distributions of W h and Zh candidates for evidence of a localised excess in the mass range of 220 GeV up to 5 TeV. No significant excess is observed and the results are interpreted in terms of constraints on the production cross-section times branching fraction of heavy W' and Z' resonances in heavy-vector-triplet models and the CP-odd scalar boson A in two-Higgs-doublet models. Upper limits are placed at the 95% confidence level and range between 9.0 × 10 -4 pb and 7.3 × 10 -1 pb depending on the model and mass of the resonance.« less